To provide tissues for research purposes, it is therefore necessary to process tumors in a uniform manner, with tissue saved in a variety of standard ways. The direct support and/or guidance from a Neuropathology Core provides a means of ensuring: 1.) that all tissues are processed in the same, technically adequate way; 2.) that all specimens are analyzed by an experienced pathologist; 3.) that all human tumors are classified, analyzed and graded in a uniform manner; 4.) that appropriately processed experimental tissues are available for all researchers.